1952 Johnson 25HP (RD-13) crank seal?

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  • June 8, 2018 at 9:56 pm #10200
    jpatti75
    Participant

      US Member

      Started working on a nice RD-13 that has been sitting in the shop for a number of years. While going over the ignition (another non-runner reported to be a runner) and finding a dead coil, I noticed the whole armature plate and ignition components are very oily, and lots of it is already gummed up. I assume this points to a faulty top crankshaft seal, but this one has a different seal than I am used to. I removed the spring and retaining washer under the ignition cam. Is it possible to pull the seal, or do I need to split the crank case open to get it out? This may be a dumb question, but is there an option to replace that upper retainer washer under the spring with a lip seal?

      It’s all a big oily mess right now, so I am hoping this repair is easier than it looks.

      Thanks,
      JP

      June 8, 2018 at 10:56 pm #77682
      frankr
      Participant

        US Member

        There is a carbon seal under the spring and washer. Simply lift it out. There is an o-ring inside it, so it will have some resistance to sliding up the shaft. Careful, it is fragile. Maybe already broken (causing the leak).

        June 9, 2018 at 12:31 am #77684
        jpatti75
        Participant

          US Member

          Thanks, Frank! I’ll be heading down to the shop momentarily to give it a look and start the clean-up process.

          Changing gears a bit, I noticed the recoil pawls have scraped the top of the flywheel ever so slightly. The recoil itself seems to be working as it should, so do I possibly need to shim it up ever so slightly with some washers?

          Man, these motors sure give your shoulder a work out trying to start them.

          JP

          June 9, 2018 at 12:35 am #77685
          david-bartlett
          Participant
            quote jpatti75:

            When properly tuned, they start great. Mine starts in 2 pulls cold, and one pull all day after that! The old style recoil doesn’t give much mechanical advantage though.

            Man, these motors sure give your shoulder a work out trying to start them.

            JP

            June 9, 2018 at 1:20 am #77688
            chris-p
            Participant

              Check for bearing wear. Try to move your flywheel fore and aft. Perhaps top bearing is shot, causing seal failure, and rubbing of the recoil.

              Hopefully not.

              June 9, 2018 at 3:02 am #77697
              jpatti75
              Participant

                US Member

                Thanks for the tips, guys!

                Although, I’ll try again tomorrow, I did try to move the crankshaft fore to aft, and didn’t notice any play. Maybe the previous owner didn’t have the flywheel torqued down to spec?

                The o-ring in the carbon seal was a little brittle, so hopefully replacing it solves the issue (fingers crossed). Could someone confirm that the part number for that o-ring is 302540?

                Got all of the oil and dried up old grease off the armature plate tonight and dug up a good coil to replace the dead one. Going to give the condensers a test, too. Hopefully when I get the new o-ring and get everything back together I’ll be able to report that it starts in two pulls like Dave’s!

                JP

                June 9, 2018 at 3:15 am #77699
                david-bartlett
                Participant

                  302540 is the correct part #. If you want, I have some Quad rings for these I can give you. I have several. PM me with your address and I will send them to you.

                  June 9, 2018 at 3:23 am #77701
                  jpatti75
                  Participant

                    US Member

                    PM sent, David. Thank you very much!

                    June 12, 2018 at 11:08 pm #77832
                    jpatti75
                    Participant

                      US Member

                      Is the o-ring installed “dry” or should I use some non-hardening sealant on it?

                      Thanks,
                      JP

                      June 13, 2018 at 12:13 am #77833
                      frankr
                      Participant

                        US Member

                        Oil or Vaseline

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